It has been known for some time that phosphates, including long chain linear polyphosphates, when introduced into the blood stream of mammals will selectively seek out and collect in the bone or skeletal structure. Pro. Soc. Exp. Biol Med. Volume 100, pages 53-55 (1959); Journal of Labelled Compounds, April-June 1970, Vol. VI, No. 2, pages 166-173; Journal of Nuclear Medicine, Vol. 11, No. 6, pages 380-381, 1970; Journal of Nuclear Medicine, Vol. 1, No. 1, January 1960, pages 1-13. In these cases a phosphorous atom or atoms of the phosphate are radioactive, i.e. .sup.32 P.
It has also been known for some time that technetium-99m (.sup.99m Tc) is a preferred radionuclide for radioactively scanning organs because of its short half life and because it radiates gamma rays which can be easily measured, compared, for example, to beta rays. See Radiology, Vol. 99, April 1971, pages 192-196.
It has also been known for some time to use divalent stannous tin (Sn.sup.+.sup.+) in the form of stannous chloride, or divalent iron (Fe.sup.+.sup.+) or reduced zirconium to bind radioactive .sup.99m Tc to carriers, such as chelating agents, red blood cells, albumin and other proteins, which selectively seek out certain organs of the body, in order to carry the .sup.99m Tc with them to such organs of the body where it is concentrated, whereby such organ can be radioactively scanned or imaged for diagnostic or other purposes, e.g. radioactive treatment of a pathological condition. See Journal of Nuclear Medicine, Vol. 11, No. 12, 1970, page 761; Journal of Nuclear Medicine, Vol. 12, No. 1, 1971, pages 22-24; Journal of Nuclear Medicine, Vol. 13, No. 2, 1972, pages 180-181; Journal of Nuclear Medicine, Vol. 12, No. 5, May 1971, pages 204-211; Radiology, Vol. 102, January 1972, pages 185-196; Journal of Nuclear Medicine, Vol. 13, No. 1, 1972, pages 58-65.
Also, it has been suggested to label a stannous compound with .sup.99m Tc for radioactively imaging bone marrow, Journal of Nuclear Medicine, Vol. 11, 1970, pages 365-366.
It has also been known for some time that the stannous ion Sn.sup.+.sup.+ forms soluble complexes with long chain polyphosphates, Journal Inorganic Nuc. Chem., Vol. 28, 1966, pages 493-502.
It has been suggested to employ the aforesaid .sup.99m Tc for radioactively scanning the skeletal bone structure of mammals by complexing or binding it to tripolyphosphate carrier by use of the aforesaid stannous ion as a binding agent in order for such phosphate to selectively carry the .sup.99m Tc to, and concentrate it in, the skeletal bone structure upon in vivo intravenous administration for subsequent radioactive scanning or imaging the skeletal structure. Radiology, Vol. 99, April 1971, pages 192-196. The use of .sup.99m Tc in this manner is alleged to have certain advantages over the use of strontium, e.g. .sup.85 Sr, as the radioactive label which has been used for radioactive bone scanning in the past. These advantages are those which are inherent in .sup.99m Tc, i.e. short half life and pure, near optimal energy gamma rays. However, the bone uptake (the percent of the total dosage which becomes concentrated in the skeletal structure within a certain time after in vivo intravenous administration) of such .sup.99m Tc-containing complex and the ratios of such bone uptake of the .sup.99m Tc by the other organs of the body (the higher these ratios the better), i.e. radioactive contrast, are not nearly as high as with radioactive strontium.